Circuit Description
The sunload sensor assembly is a light sensitive photocell. The instrument panel module (IPM) determines the ambient light based on the voltage from the sunload sensor assembly. The IPM controls the headlamp automatic on/off and delayed off functions.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B2646 Ambient Light Sensor Circuit Range
Conditions for Running the DTC
The IPM is powered.
Conditions for Setting the DTC
The sunload sensor assembly voltage is less than 0.09 or greater than 4.8 volts.
Action Taken When the DTC Sets
| • | Set the variable ambient light status to Low Light. |
| • | The IPM sets a DTC. |
Conditions for Clearing the DTC
The IPM does not detect a voltage that is less than or greater than the predetermined value during the diagnostic self test.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests for the proper operation of the circuit in the high voltage range.
-
This step tests for the proper operation of the circuit in the low voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to battery positive voltage.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics Connector End View Reference: Computer/Integrating Systems Connector End Views in Computer/Integrating Systems or Lighting Systems Connector End Views | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 |
Does the scan tool indicate the voltage is within the specified range? | 0.09-4.8 V | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 |
Does the scan tool indicate that the Ambient Light Sensor data parameter is greater than the specified value? | 4.8 V | Go to Step 4 | Go to Step 5 | |
Does the scan tool indicate that the Ambient Light Sensor data parameter is less than the specified value? | 0.09 V | Go to Step 8 | Go to Step 6 | |
5 | Test the ambient light sensor signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 9 |
6 | Test the ambient light sensor signal circuit for a short to battery positive voltage, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 7 |
7 | Test the low reference circuit for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 9 |
8 | Inspect for poor connections at the harness connector of the sunload sensor assembly. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 10 |
9 | Inspect for poor connections at the harness connector of the IPM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 11 |
10 | Replace the sunload sensor assembly. Refer to Sunload and Twilight Sentinel Sensor Replacement in Instrument Panel, Gages, and Console. Did you complete the replacement? | -- | Go to Step 12 | -- |
11 | Replace the IPM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 12 | -- |
12 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
